Evaluation of the solar contribution in a hybrid incubator of avian eggs

Abstract

Solar thermal energy has been widely employed by the agro food industry with the objectives of reducing conventional sources of energy and achieving a reduction in greenhouse gas emissions. The focus of this manuscript is to evaluate a medium scale commercial incubator (for 9072 red-legged partridge (Alectoris rufa) eggs) supported with solar thermal energy under detailed monitoring. In this sense, an evacuated solar collector with an absorbing area of 0.99 and 163 L of water accumulation (with an auxiliary 80 L water tank) was coupled to the original emergency cooling system of the incubator. The hybrid system, using an automated control system, showed higher thermal stability (std=0.12°C) than the standard control system of the incubator (std=0.18°C). The area of the polygon defined by the phase space (PS) diagram, involving >90% of the data for the experiments with solar contribution (Experiments 1 to 3), was among 27% to 35% of that of commercial incubations, which is because of the high stability in the temperature. The computed performance (0.44 to 0.85) of the evacuated tube collector was in the same range as the theoretical performance provided by the manufacturer (0.60). The solar contribution was up to 60.4% per day, which indicates a saving of 806 MJ of electricity in a standard incubation.